This invention relates to an apparatus for automatically mounting wheels equipped with tires in an assembly process of automobiles.
Automation of the assembly process of automobiles requires an apparatus for automatically mounting wheels on hubs of automobiles.
An automatic wheel mounting apparatus comprises a robot for positioning the wheels on the hubs and applying and tightening nuts, a nut supplying device for supplying the robot with nuts, and, a device for supplying tires. In this case, when the robot positions a wheel onto a hub and threads the nuts onto the hub studs, the hub must be oriented in a predetermined position, and the position of the hub studs must be aligned with the position of blot holes in the wheel.
In an assembly line, in general, the automobile is carried on a shuttle and, at a wheel mounting pit, a lower arm of thee automobile suspension is pushed up by a lifting device to position the hub. However, even if pushed up by a fixed amount, although the camber angle can be cancelled, the hub is not always oriented in the same position. The position varies with vehicles type, and especially with the steering angle. As a result, the robot may sometimes fine it to be impossible to mount a wheel on a hub.
Furthermore, the rotational position of the hub studs varies with the rotational position of the hub. The positioning mechanism of the robot for handling the wheel and the nuts thus becomes complicated in order to align the rotational position of the wheel and nuts with the rotational position of the hub studs. In addition, a sensor is required for detecting the position of the hub stubs.
An automatic wheel mounting apparatus is described in Japanese Patent Publication Laid-Open No. 59-227505/1984. However, this apparatus is complex in structure and involves a large number of steps for the mounting operation. In this apparatus, the angle position of the hub is set against the studs by pushing an inclined regulating plate. This requires a large pushing force, is slow in setting speed, and it is difficult to achieve precision setting. Furthermore, wheel mounting is difficult when the hub is inclined due to a large steering angle.